That He Himself is both Judge and King
In the seventy-first Psalm: “O God, give Your judgment to the king, and Your righteousness to the king's son, to judge Your people in righteousness.” Also in the Apocalypse: “And I saw the heaven opened, and behold a white horse; and He who sate upon him was called Faithful and True; and He judges justice and righteousness, and makes war. And His eyes were. as it were, a flame of fire, and upon His head were many crowns; and He bare a name written that was known to none other than Himself': and He was clothed with a garment sprinkled with blood, and His name is called the Word of God.
And the armies which are in heaven followed Him on white horses, clothed in linen white and Clean. And out of His mouth went forth a sword with two edges, that with it He should smite the nations, which He shall shepherd with a rod of iron; and He shall tread the winepress of the wrath of God Almighty. Also He has on His garment and on His thigh the name written, King of kings, and Lord of lords.” Likewise in the Gospel: “When the Son of man shall come in His glory, and all the angels with Him, then He shall sit in the throne of His glory; and all nations shall be gathered together before Him, and He shall separate them one from another, even as a shepherd separates the sheep from the goats; and He shall place the sheep at His right hand, but the goats at His left hand.
Then shall the King say unto them who shall be at His right hand, Come, you blessed of my Father, receive the kingdom which is prepared for you from the beginning of the world: for I was hungry, and you gave me to eat: I was thirsty, and you gave me to drink: I was a stranger, and you received me: naked, and you clothed me: sick, and you visited me: I was in prison, and you came unto me. Then shall the righteous answer, and say unto Him, Lord, when saw we You hungry, and fed You?
Thirsty, and gave You to drink? And when saw we You a stranger, and received You? Naked, and clothed You? And when saw we You sick, and in prison, and came unto You? And the King, answering, shall say unto them, Verily I say unto you, In as far as you have done it to the least of these my brethren, you have done it unto me. Then shall He say unto them who shall be on His left hand, Depart from me, you cursed, into everlasting fire, which my Father has prepared for the devil and his angels: for I have been hungry, and you gave me not to eat: I have been thirsty, and you gave me not to drink: I was a stranger, and you received me not: naked, and you clothed me not: sick, and in prison, and you visited me not.
Then shall they also answer and say, Lord, when saw we You hungry, or thirsty, or a stranger, or naked, or sick, or in prison, and have not ministered unto You? And He shall answer unto them, Verily I say unto you, Inasmuch as you have not done it to one of the least of these, you have not done it unto me. And these shall go away into everlasting burning, but the righteous into life eternal.”
Source: The Treatises of Cyprian (New Advent)